Do you need a new ECM after engine swap?
Thread Starter
Newbie
Joined: Apr 2021
Posts: 1
Likes: 1
C400
Do you need a new ECM after engine swap?
Long story short I got an engine swap on my 2015 Mercedes C400 for the same exact engine. Everything went well except I needed to get it programmed so that it will start. Dealership is telling me I need to buy a brand new ECM because the one from the new used engine can’t be programmed to my vehicle. Is this true? I’m being quoted $2500 for the job. Any help is appreciated. Thanks in advance
Senior Member
Joined: Mar 2018
Posts: 323
Likes: 103
From: Central Florida
'15 C400 and '15 ML350
Long story short I got an engine swap on my 2015 Mercedes C400 for the same exact engine. Everything went well except I needed to get it programmed so that it will start. Dealership is telling me I need to buy a brand new ECM because the one from the new used engine can’t be programmed to my vehicle. Is this true? I’m being quoted $2500 for the job. Any help is appreciated. Thanks in advance
As for the ECU, you should be able to find someone with the proper software/hardware suite that can reflash the replacement ECU with your VIN. There are several people who have gotten junk yard ECU's and flashed them to their car as a spare ECU with different performance map.
I could see the dealer not wanting to do any of this work, but a 3rd part shop should.
